The invention concerns an apparatus and method for training adjustment in sports, particularly running sports.
To generate muscle power/performance, a human or other muscle requires oxygen that must be supplied by the organism. The greater the power, the greater the need for oxygen as well. At a certain power limit, the body will go into what is known as “oxygen debt”. This means that the blood contains too small an oxygen ratio to be able to supply the oxygen necessary to generate power. The metabolism in the muscle then passes into the anaerobic range marked by oxygen deficiency. In contrast to this, the metabolism given sufficient oxygen supply is designated as aerobic.
Complete burning of the energy carrier glucose drawn on by the body does not ensue in the muscle in the anaerobic range. As a result of this, “combustion shortfalls” accumulate in the body that can no longer completely metabolized as a result of the oxygen deficiency. The muscle thus stressed is “acidic” and requires a longer time in order to regenerate after the stress.
In sport types that are connected with high body stress, particularly running sports, it is therefore important that the training is implemented predominantly in the aerobic range, and only a small portion in the anaerobic range. For a non-professional athlete, for example, the aerobic training phase should amount to approximately 80% of the overall training.
For training adjustment, it is typical in sports medicine to determine what is known as the lactate balance point (LBP). Lactate (lactic acid) is a decomposition product of glucose that—as specified in the preceding—is created when the oxygen in the organism is no longer sufficient for combustion. In the anaerobic range, lactate therefore accumulates in the body, while in the aerobic range, excess lactate is metabolized again. At the threshold between aerobic metabolism and anaerobic metabolism, the lactate level in the organism remains in balance. This defines the LBP. If the LBP and the associated heart rate of an athlete are known, the athlete can optimize his training according to this.
The lactate value is conventionally determined with a lactate measurement device which effects a blood analysis of blood samples that are extracted from the athlete at different stresses. Physiological fundamentals and a method for lactate measurement are, for example, specified in German Patent Document DE 199 09 852 A1. The known solution is, disadvantageously, an invasive method, especially since blood samples must be extracted from the test person (e.g., an athlete) to be tested. This is, on the one hand, sometimes painful for the athlete. On the other hand, the blood extraction is always connected with a risk of infection, for example, with hepatitis or HIV, for both the test person and for the examiner. To reduce this infection risk, high hygiene standards are in turn necessary that make the method elaborate and expensive.
A conventional non-invasive method to determine the LBP, designated as a “Conconi test”, is increasingly being used in sports medicine. In this method, a test person runs on a 400 m athletic track for a length of 200 m with a predetermined speed, for example 8 km/h. After respectively 200 m, the test person increases the tempo in stages, for example, by respectively 0.5 km/h. At each 200 m mark of the athletic track, the test person notes his current heart rate and calls it out to an attendant after respectively circling the athletic track. The test person runs on the track until he has reached a power limit, meaning he cannot further increase the speed.
For test evaluation, the heart rate is plotted against the associated running speed in a two-dimensional (X-Y) diagram. A characteristic finding hereby results: in the aerobic range, given a comparably low power, the heart rate runs nearly linearly with the running speed. This means that the heart rate increases in the same proportion as the power generated by the test person. This regularity is broken at the threshold to the anaerobic metabolism. In the anaerobic high-power range, the heart rate increases comparatively only slightly with further-increasing power or, respectively, running speed. The function of the heart rate dependent on the running speed thus shows a clear, more or less sharp break at the transition from the aerobic low-power range to the anaerobic high-power range, via which the LBP is determined. The heart rate characteristic for the LBP and the associated running speed can be simply read from the X/Y diagram.
However, the Conconi test is comparably elaborate and can hardly be executed without a trained attendant. Additionally, with the Conconi test the LBP can be determined only comparatively imprecisely, due to the weather dependency and the capability of the test person to precisely control his speed.